A secret sharing scheme based on exponentiation in Galois fields

To provide more efficient and flexible alternatives for the applications of secret sharing schemes, this paper describes a threshold sharing scheme based on exponentiation of matrices in Galois fields. A significant characteristic of the proposed scheme is that each participant has to keep only one master secret share which can be used to reconstruct different group secrets according to the number of threshold values.

Crypto at the Time of Surveillance: Sharing with the Cloud

These days as we are facing extremely powerful attacks on servers over the Internet (say, by the Advanced Persistent Threat attackers or by Surveillance by powerful adversary), Shamir has claimed that “Cryptography is Ineffective”and some understood it as “Cryptography is Dead!” In this talk I will discuss the implications on cryptographic systems design while facing such strong adversaries. Is crypto dead or we need to design it better, taking into account, mathematical constraints, but also systems vulnerability constraints. Can crypto be effective at all when your computer or your cloud is penetrated? What is lost and what can be saved? These are very basic issues at this point of time, when we are facing potential loss of privacy and security.

Fashions and fads in finance: contingent emulation and the political economy of sovereign wealth fund creation. IHS Political Science Series No. 131, July 2012

Sovereign wealth funds (SWFs), government-owned or managed investment vehicles, have proliferated at a remarkable rate over the past decade, even as political controversy has surrounded them. Why? The extant literature depicts the process of SWF creation as driven by functional imperatives associated with “excess” revenue and reserves accumulated from commodity booms and large current account surpluses. I argue that SWF creation also reflects in large part a process of contingent emulation in which first this policy has been constructed as appropriate for countries with given characteristics, and then when countries took on these characteristics, they followed their peers. Put simply, fashions and fads in finance matter for policy diffusion. I assess this argument using a new dataset on SWF creation that covers nearly 80 countries from 1984 to 2007. The results suggest peer-based contingent emulation has been a crucial factor shaping the decision of many countries to create a SWF, especially among fuel exporters. An earlier version of this paper was presented at the annual meeting of the American Political Science Association, Washington, DC, 2 – 5 September 2010. The author would like to thank Eric Neumayer for his many suggestions and comments on previous versions of the manuscript. The author would also like to thank Zachary Elkins for sharing data. Finally, the author would like to acknowledge the research assistance of Natali Bulamacioglu and Christopher Gandrud.

Military Capabilities: From Pooling & Sharing to a Permanent and Structured Approach. Security Policy Brief No. 37, September 2012

In 2013 the European Council for the first time since long will deal with European defence. An excellent opportunity: to move key Pooling & Sharing projects to the implementation stage in the short term, and to launch a permanent and structured approach to the development of European military capabilities for the long term.